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| #34900 (Received by flhurricane at: 11:00 AM 23.Jul.2005) TCDAT1 TROPICAL STORM FRANKLIN DISCUSSION NUMBER 9 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 11 AM EDT SAT JUL 23 2005 RECENT REPORTS FROM AN AIR FORCE RECON AIRCRAFT INDICATE FRANKLIN HAS BECOME MUCH BETTER ORGANIZED AND HAS STRENGTHENED...POSSIBLY EVEN TO HURRICANE STRENGTH. A DROPSONDE REPORT AT 1337Z MEASURED SURFACE WINDS OF 59 KT IN THE SOUTHEAST QUADRANT WHERE THE FLIGHT CREW HAS BEEN ESTIMATING 60-65 KT WINDS...EVEN THOUGH THE CENTRAL PRESSURE IS STILL ABOVE 1000 MB. THE INITIAL INTENSITY IS BEING INCREASED TO 60 KT FOR THIS ADVISORY...BUT THE INTENSITY COULD BE HIGHER SINCE FRANKLIN IS EMBEDDED IN A REGION OF MUCH HIGHER THAN AVERAGE SURFACE PRESSURES. THE INITIAL MOTION ESTIMATE IS 055/08...BASED ON THE PAST 9 HOURS OF RECON FIXES. THE CENTER OF FRANKLIN IS LOCATED NEAR THE NORTHWEST PORTION OF THE COLD CDO CLOUD SHIELD AND IS SHOWING SIGNS OF BECOMING BETTER ORGANIZED IN SATELLITE IMAGERY THAN WHAT MOST OF THE GLOBAL MODELS HAVE BEEN INDICATING. THE STRONG SHORTWAVE NOW APPROACHING THE U.S. EAST COAST HAS MOST OF ITS ENERGY FROM NORTH CAROLINA NORTHWARD...WITH ONLY 5-10 WEST-NORTHWESTERLY MID-LEVEL FLOW INDICATED SOUTH OF THE CAROLINAS. MOST OF THE MODEL GUIDANCE ...EXCLUDING THE MUCH FASTER GFS AND GFDL MODELS...NOW SLOWS DOWN FRANKLIN THROUGH 72 HOURS AND EITHER DISSIPATED THE CYCLONE OR WAITS FOR ANOTHER SHORTWAVE TROUGH TO PICK UP THE CYCLONE AND ACCELERATE IT QUICKLY TO THE NORTHEAST. JUST ONE PROBLEM...ALL OF THE MODELS...TO SOME DEGREE...MOVE THE MID-LEVEL CIRCULATION SLOWLY BACK TO THE SOUTH AND SOUTHWEST AFTER 72 HOURS. THIS SCENARIO IS SIMILAR TO THE MEDIUM AND DEEP BAM MODELS. GIVEN THAT FRANKLIN IS CURRENTLY SOUTH OF AND SLOWER THAN ALL OF THE NHC MODEL GUIDANCE FROM 06Z...AND THAT ALL OF THE MODELS FORECAST THE MID-LEVEL FLOW TO BECOME NORTHWEST TO NORTHERLY BY 72 HOURS...THE OFFICIAL TRACK HAS BEEN SHIFTED TO THE RIGHT...OR SOUTH...OF AND A LITTLE SLOWER THAN THE PREVIOUS FORECAST. THIS TRACK IS CONSISTENT WITH THE GUNS MODEL CONSENSUS. FRANKLIN REMAINS RELATIVELY SMALL TROPICAL CYCLONE...BUT WITH A WELL-DEFINED INNER CORE WIND FIELD. AS SUCH...SMALL CHANGES IN THE CENTRAL DEEP CONVECTION CAN RESULT IN SIGNIFICANT CHANGES IN INTENSITY. GIVEN THE TENACITY OF THIS CYCLONE OVER THE PAST FEW DAYS THAT HAS DEFIED FAIRLY SIGNIFICANT VERTICAL SHEAR...IT APPEARS THAT THIS SYSTEM WILL PROBABLY GO ON AND BECOME A HURRICANE WITH A CENTRAL PRESSURE ABOVE 995 MB IN THE NEXT 12-24 HOURS. AFTER THAT...INCRESING NORTHWEST TO NORTHWESTERLY MID- TO UPPER-LEVEL FLOW SHOULD INDUCE SOME SLOW WEAKENING. FORECASTER STEWART FORECAST POSITIONS AND MAX WINDS INITIAL 23/1500Z 29.4N 75.0W 60 KT 12HR VT 24/0000Z 30.1N 73.8W 65 KT 24HR VT 24/1200Z 30.7N 72.1W 65 KT 36HR VT 25/0000Z 31.1N 70.4W 60 KT 48HR VT 25/1200Z 31.5N 68.7W 55 KT 72HR VT 26/1200Z 32.3N 66.0W 50 KT 96HR VT 27/1200Z 33.0N 63.5W 45 KT 120HR VT 28/1200Z 35.0N 59.0W 40 KT |
